A new model of aging takes into account not only genetics and environmental exposures but also the tiny changes that randomly arise at the cellular level.
University Professor Caleb Finch introduced the “Tripartite Phenotype of Aging” as a new conceptual model that addresses why lifespan varies so much, even among human identical twins who share the same genes. Only about 10 to 35 percent of longevity can be traced to genes inherited from our parents, Finch mentioned.
Finch authored the paper introducing the model with one of his former graduate students, Amin Haghani, who received his PhD in the Biology of Aging from the USC Leonard Davis School in 2020 and is now a postdoctoral researcher at UCLA. In the article, they propose that the limited heritability of aging patterns and longevity in humans is an outcome of gene-environment interactions, together with stochastic, or chance, variations in the body’s cells. These random changes can include cellular changes that happen during development, molecular damage that occurs later in life, and more.